USIM Chip Memory Segmentation for Multi-Card Payment Security
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Solution Overview
Problem
Existing financial chips, such as USIM chips, are limited to storing information for a single card company, restricting the use of multiple finance companies on a payment device without compromising security.
Innovation Solution
A method that divides the memory of a financial chip into multiple storage areas, assigns sequence numbers, and allows multiple card company servers to access and record information using unique sequence numbers and derivation keys, enabling multiple card companies to store and use their information securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single primary key is used in the USIM chip for security, then security is improved, but the ability to store multiple card company information deteriorates
Solution Approach 1:
The patent segments the storage space of the USIM chip into multiple independent storage areas, each assigned a unique sequence number. This allows multiple card company information to be stored simultaneously while maintaining the security structure through separate access paths for each segment.
Solution Approach 2:
The patent changes the access parameter from a single primary key to multiple derivation keys generated through a key derivation function. Each derivation key is associated with a specific sequence number, allowing different card company servers to access their respective storage areas independently while maintaining overall security.
2Reliability
If the primary key is changed to an issuer key after first card company installation, then security against unauthorized access is improved, but the ability for other card companies to access the USIM chip deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-allocating multiple storage areas with unique sequence numbers before any card company information is installed. This allows multiple card companies to sequentially install their information without requiring key changes, as each company is assigned a predetermined storage area accessible through its own derivation key.
Solution Approach 2:
The patent introduces a key derivation function as an intermediary mechanism that generates unique derivation keys for each card company based on their identifier and the sequence number of their storage area. This intermediary allows multiple card companies to access the USIM chip independently without interfering with each other's security.
3Adaptability or versatility
If a separate smart chip is added to support multiple card companies, then the ability to use various finance companies is improved, but device complexity and burden increase
Solution Approach 1:
The patent makes the existing USIM chip universal by enabling it to store and manage information from multiple card companies simultaneously. Through the sequence number-based storage segmentation and derivation key mechanism, the single USIM chip can serve multiple finance companies, eliminating the need for additional separate smart chips.
Data Source
AI summary
Disclosed is a method for controlling a financial chip of a payment device, in which information for multiple cards is stored in a single USIM chip, to enable the payment device to use credit cards from multiple card companies as a payment means. The method includes: dividing storage of the memory of the financial chip into multiple sections and allocating a turn to each storage section; allocating a first turn to the first card company server and recording information on the credit card issued by the first card company server, an application for financial transactions, and an identifier for the application when the first card company server and the second card company server sequentially make a request for the record of credit card information to the financial chip; and providing card arrangement information including information on the first turn and a second turn to the second card company server.